Microstructure and Hardness of Plasma Cladding Ni-Cr-C Alloy Coating

Ni-Cr-C alloy coating was prepared by plasma cladding technique on the surface of scoop tooth of dredger material low carbon martensite cast steel. The microstructure, chemical composition and micro-hardness of the cladding coating were investigated with OM, SEM, EDS, XRD and micro-hardness tester. The results show that the coating had metallurgy combination with the matrix, which was composed of eutectic γ-Fe/(Cr,Fe)7C3 and primary hard wear resistant phase (Cr,Fe)7C3 with the forms of lath or block. The densest coating was obtained with the cladding current of 100 A and the scanning velocity of 150 mm·min-1, and the micro-hardness reached up to 1 053 HV.